scholarly journals The Influence of Thinning on the Proportion of Peeler, Sawtimber, and Pulpwood Trees in Loblolly Pine Plantations

2005 ◽  
Vol 29 (3) ◽  
pp. 158-162 ◽  
Author(s):  
Ralph L. Amateis ◽  
Harold E. Burkhart
Keyword(s):  
Loblolly Pine ◽  
Significant Influence ◽  
Basal Area ◽  
Product Distribution ◽  
Pine Plantations ◽  
Thinning Intensity ◽  
Modeling Methods ◽  
Before And After ◽  
History Of

Abstract Data from a long-term, region-wide thinning study were used to examine the proportion of pulpwood, sawtimber, and peeler quality trees in unthinned, once-thinned, and twice-thinned plantations. Results suggest that the thinning treatments have had a significant influence on the product distribution in these stands over the 21-year history of the study. Proportional odds modeling methods were used to develop equations for predicting product proportions from dbh, the basal area before and after thinning (thinning intensity), and the number of thinnings imposed. South. J. Appl. For. 29(3):158–162.

scholarly journals Modeling Response to Thinning in Loblolly Pine Plantations

2000 ◽  
Vol 24 (1) ◽  
pp. 17-22 ◽  
Author(s):  
Ralph L. Amateis
Keyword(s):  
Loblolly Pine ◽  
Basal Area ◽  
Response Models ◽  
Thinning Intensity ◽  
Nonlinear Regression Models ◽  
Predictors Of Response ◽  
Cumulative Response ◽  
Before And After ◽  
Volume Response ◽  
Pinus Taeda L

Abstract Data from a thinning study established in loblolly pine (Pinus taeda L.) plantations at different locations in the southeastern United States were used to develop response models for basal area and survival following thinning. The nonlinear regression models predict total cumulative response as a function of stand and site conditions at time of thinning, thinning intensity, and elapsed time since thinning. Variables expressing thinning intensity that were significant predictors of response included before and after thinning basal areas and number of trees. The models suggest that initially after thinning, volume response declines briefly then gradually increases toward the unthinned control. Managers can use the equations presented here to evaluate the effect of alternative thinning regimes on stand development. The response equations can also be combined with baseline models for unthinned stands to predict basal area and number of trees following thinning. South. J. Appl. For. 24(1):17-22.

scholarly journals Fine-tuning citrate synthase flux potentiates and refines metabolic innovation in the Lenski evolution experiment

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Erik M Quandt ◽  
Jimmy Gollihar ◽  
Zachary D Blount ◽  
Andrew D Ellington ◽  
George Georgiou ◽  
...  
Keyword(s):  
Citrate Synthase ◽  
Fine Tuning ◽  
Ecological Niches ◽  
Glta Gene ◽  
Evolutionary Changes ◽  
Before And After ◽  
Evolution Experiment ◽  
History Of ◽  
Second Wave

Evolutionary innovations that enable organisms to colonize new ecological niches are rare compared to gradual evolutionary changes in existing traits. We discovered that key mutations in the gltA gene, which encodes citrate synthase (CS), occurred both before and after Escherichia coli gained the ability to grow aerobically on citrate (Cit+ phenotype) during the Lenski long-term evolution experiment. The first gltA mutation, which increases CS activity by disrupting NADH-inhibition of this enzyme, is beneficial for growth on the acetate and contributed to preserving the rudimentary Cit+ trait from extinction when it first evolved. However, after Cit+ was refined by further mutations, this potentiating gltA mutation became deleterious to fitness. A second wave of beneficial gltA mutations then evolved that reduced CS activity to below the ancestral level. Thus, dynamic reorganization of central metabolism made colonizing this new nutrient niche contingent on both co-opting and overcoming a history of prior adaptation.

Priming-Induced Shift in Synaptic Plasticity in the Rat Hippocampus

1999 ◽  
Vol 82 (4) ◽  
pp. 2024-2028 ◽  
Author(s):  
Hongyan Wang ◽  
John J. Wagner
Keyword(s):  
Synaptic Plasticity ◽  
Hippocampal Slices ◽  
Long Term Potentiation ◽  
Crossover Point ◽  
Term Potentiation ◽  
Before And After ◽  
History Of ◽  
The Brain ◽  
Dependent Mechanism

The activity history of a given neuron has been suggested to influence its future responses to synaptic input in one prominent model of experience-dependent synaptic plasticity proposed by Bienenstock, Cooper, and Munro (BCM theory). Because plasticity of synaptic plasticity (i.e., metaplasticity) is similar in concept to aspects of the BCM proposal, we have tested the possibility that a form of metaplasticity induced by a priming stimulation protocol might exhibit BCM-like characteristics. CA1 field excitatory postsynaptic potentials (EPSPs) obtained from rat hippocampal slices were used to monitor synaptic responses before and after conditioning stimuli (3–100 Hz) of the Schaffer collateral inputs. A substantial rightward shift (>5-fold) in the frequency threshold between long-term depression (LTD) and long-term potentiation (LTP) was observed <1 h after priming. This change in the LTD/P crossover point occurred at both primed and unprimed synaptic pathways. These results provide new support for the existence of a rapid, heterosynaptic, experience-dependent mechanism that is capable of modifying the synaptic plasticity phenomena that are commonly proposed to be important for developmental and learning/memory processes in the brain.

scholarly journals A New Whole-Stand Model for Unmanaged Loblolly and Slash Pine Plantations in East Texas

2009 ◽  
Vol 33 (2) ◽  
pp. 69-76 ◽  
Author(s):  
Dean W. Coble
Keyword(s):  
Loblolly Pine ◽  
Basal Area ◽  
Pinus Elliottii ◽  
Current Data ◽  
Slash Pine ◽  
Pine Plantations ◽  
Growth And Yield ◽  
East Texas ◽  
Age Classes ◽  
Yield Model

Abstract A new compatible whole-stand growth-and-yield model to predict total tree cubic-foot volume per acre yield (outside and inside bark) was developed for unmanaged loblolly pine (Pinus taeda) and slash pine (Pinus elliottii) plantations in East Texas. This model was compared with the noncompatible whole-stand model of Lenhart (<xref ref-type="bibr" rid="B15-2127">Lenhart, 1996</xref>, Total and partial stand-level yield prediction for loblolly and slash pine plantations in east Texas, South. J. Appl. For. 20(1):36–41) and the <xref ref-type="bibr" rid="B15-2127">Lenhart (1996)</xref> model refit to current data. For the two species, all three models were evaluated with independent observed data. The model developed in this study outperformed both Lenhart models in prediction of future yield and basal area per acre for all age classes combined and by 5-year age classes. The Lenhart models consistently overestimated yield and basal area per acre. All three models predicted surviving trees per acre similarly. An example is also provided to show users how to use the new whole-stand model.

Postthinning growth and yield of row-thinned and selectively thinned loblolly and slash pine plantations

1989 ◽  
Vol 19 (2) ◽  
pp. 247-256 ◽  
Author(s):  
V. C. Baldwin Jr. ◽  
D. P. Feduccia ◽  
J. D. Haywood
Keyword(s):  
Loblolly Pine ◽  
Unit Area ◽  
Basal Area ◽  
Site Index ◽  
Slash Pine ◽  
Pine Plantations ◽  
Growth And Yield ◽  
Growth Responses ◽  
Diameter Increment ◽  
Study Results

This study compared growth responses in planted loblolly pine (Pinustaeda L.) and slash pine (P. elliottii Engelm.) stands thinned by using three row-felling methods and at the same density levels, three selective felling methods. The study plots were in six plantations, aged 15–22 years, located in central Louisiana. Growth was measured 5 and 10 years after plot installation. Site index varied from 19.5 to 31.7 m (base age 50) and initial planting densities ranged from 1993 to 2989 trees/ha. Study results show there will likely be less diameter increment and less net basal area and cubic-metre volume per unit area growth and yield, and the growth will be in smaller-sized trees, if row thinning is used rather than selective thinning from below. These differences will probably be greater in slash pine plantations than in loblolly pine plantations.

scholarly journals New historical data for long-term swordfish ecological studies in the Mediterranean Sea

2021 ◽  
Vol 13 (12) ◽  
pp. 5867-5877
Author(s):  
Brian R. MacKenzie ◽  
Teresa Romeo ◽  
Piero Addis ◽  
Pietro Battaglia ◽  
Pierpaolo Consoli ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Fishery Management ◽  
Data Availability ◽  
Knowledge Based ◽  
Time Period ◽  
Before And After ◽  
Trap Fishery ◽  
History Of ◽  
The Mediterranean

Abstract. Management of marine fisheries and ecosystems is constrained by knowledge based on datasets with limited temporal coverage. Many populations and ecosystems were perturbed long before scientific investigations began. This situation is particularly acute for the largest and commercially most valuable species. We hypothesized that historical trap fishery records for bluefin tuna (Thunnus thynnus Linnaeus, 1758) could contain catch data and information for other, bycatch species, such as swordfish (Xiphias gladius Linnaeus, 1758). This species has a long history of exploitation and is presently overexploited, yet indicators of its status (biomass) used in fishery management only start in 1950. Here we examine historical fishery records and logbooks from some of these traps and recovered ca. 110 years of bycatch data (1896–2010). These previously neglected, but now recovered, data include catch dates and amounts in numbers and/or weights (including individual weights) for the time period before and after major expansion of swordfish fisheries in the Mediterranean Sea. New historical datasets such as these could help understand how human activities and natural variability interact to affect the long-term dynamics of this species. The datasets are online and available with open access via three DOIs, as described in the “Data availability” section of the article.

Color Aerial Photography for Assessing the Need for Fertilizers in Loblolly Pine Plantations

1988 ◽  
Vol 12 (4) ◽  
pp. 270-273 ◽  
Author(s):  
Charles R. Blinn ◽  
Al Lyons ◽  
Edward R. Buckner
Keyword(s):  
Pinus Taeda ◽  
Loblolly Pine ◽  
Aerial Photography ◽  
Basal Area ◽  
Site Index ◽  
Pine Plantations ◽  
Color Coding ◽  
Foliar N ◽  
Significant Relationships ◽  
Pinus Taeda L

Abstract Color aerial photography was used to assess crown color classes in loblolly pine (Pinus taeda L.) plantations. Three distinct Munsell color classes were delineated on the resulting photographs. Foliar N levels and, to a lesser degree, foliar K levels were directly related to color. Significant relationships between color and site index and color and basal area were shown. Application of color aerial photography, combined with Munsell color coding, could expedite land classification and also make possible more efficient use of fertilizers. South J. Appl. For. 12(4):270-273.

scholarly journals Growth and Yield Relative to Competition for Loblolly Pine Plantations to Midrotation—A Southeastern United States Regional Study

2003 ◽  
Vol 27 (4) ◽  
pp. 237-252 ◽  
Author(s):  
James H. Miller ◽  
Bruce R. Zutter ◽  
Shepard M. Zedaker ◽  
M. Boyd Edwards ◽  
Ray A. Newbold
Keyword(s):  
Loblolly Pine ◽  
Basal Area ◽  
Pine Plantations ◽  
Growth And Yield ◽  
Regional Study ◽  
Annual Increment ◽  
Complete Control ◽  
High Severity ◽  
Pinus Taeda L ◽  
Mean Annual Increment

Abstract Loblolly pine (Pinus taeda L.) plantations were studied across 13 southeastern sites grown for 15 yr with near-complete control of woody, herbaceous, and woody plus herbaceous components during the first 3–5 yr. This multiple objective experiment (the COMProject) documents stand dynamics at the extreme corners of the response surface that encompasses most competition conditions common to pine plantations. This is the second of two companion reports. Merchantable pine volume after 15 yr with early, near complete competition control reached 2,350–4,415 ft3/ac by site compared to 1,132–2,965 ft3/ac on the no controls. With control of both woody and herbaceous competition, 15 yr volumes were increased by 23–121% and gains increased as hardwoods and shrubs increased on the no controls. Early woody control increased merchantable pine volume on 11 sites by 14–118%, while herbaceous control yielded somewhat less on average, a 17–50% increase on ten sites. No gains and some volume losses occurred when control of one component released severe competition from an enhanced remaining component, otherwise gains were generally additive for control of both components. Pine volume was decreased by about 1% for each 1 ft2/ac of hardwood basal area (BA) present at age 15. Annual measurements determined that culmination of current annual increment (CAI) with control of both competition components occurred in yr 8–11 at 250–470 ft3/ac/yr. CAIs for pine height, BA, and volume were decreased by about 5–27% when growing season rainfall (March–October) was less than 36 in. Mean annual increment had not culminated for any treatment at any location by yr 15 and ranged from 195–250 ft3/ac/yr with both woody and herbaceous control. Fusiform rust mainstem galls [Cronartium quercuum (Berk.) Miyabe ex Shirai f. sp. fusiforme (Hedge. & Hunt) Burdsall & Snow] in high severity areas increased additively with control of both components, more so with herb control. Contrary to the widespread assumption that hardwood out-compete pine, the hardwood proportion of stand BA decreased from yr 5–15 on sites where hardwood BA in yr 5 exceeded 10 ft2. South. J. Appl. For. 27(4):237–252.

Removal of Competing Vegetation from Established Loblolly Pine Plantations Increases Growth on Piedmont and Upper Coastal Plain Sites

1996 ◽  
Vol 20 (4) ◽  
pp. 188-193 ◽  
Author(s):  
James C. Fortson ◽  
Barry D. Shiver ◽  
Lois Shackelford
Keyword(s):  
Loblolly Pine ◽  
Coastal Plain ◽  
Basal Area ◽  
Pine Plantations ◽  
Slope Position ◽  
Age Classes ◽  
Individual Tree ◽  
Competing Vegetation ◽  
Positive Treatment ◽  
The Individual

Abstract A series of paired plots was installed in loblolly pine plantations at 42 locations in Georgia's Piedmont and Alabama's Piedmont and Coastal Plain. One plot of each pair had all competing vegetation eliminated. The other plot was left as an uncontrolled check. Locations were stratified over two age classes (5-9 and 12-16 yr old) and three slope positions (top, midslope, and bottom). Analysis of 33 surviving locations 8 yr after treatment revealed a positive treatment effect for both individual tree (dbh and total height) and stand characteristics (basal area per acre, total volume per acre, and merchantable volume per acre). There was no difference in volume response between age classes. Slope position was not significant for the individual tree variables, but was significant for the stand variables, with midslopes responding most positively followed by bottom and then top slope positions. Over all locations, the average treatment response was approximately ½ cord/ac/yr. Economic analyses indicate that the magnitude of the response will be economical for many stumpage prices, particularly on midslope and bottom slope positions, in plantations where access and species composition make herbicide spraying possible. South J. Appl. For. 20(4):188-192.

Wood density in Norway spruce: changes with thinning intensity and tree age

2005 ◽  
Vol 35 (7) ◽  
pp. 1767-1778 ◽  
Author(s):  
Tuula Jaakkola ◽  
Harri Mäkinen ◽  
Pekka Saranpää
Keyword(s):  
Norway Spruce ◽  
Wood Density ◽  
Basal Area ◽  
Tree Age ◽  
Individual Tree ◽  
Thinning Intensity ◽  
Individual Tree Growth ◽  
Spruce Stands ◽  
Individual Trees

The effect of thinning intensity on growth and wood density in Norway spruce (Picea abies (L.) Karst.) was investigated in two long-term thinning experiments in southeastern Finland. The stands were approaching maturity, and their development had already been studied for 30 years. The intensities of thinning were low, normal, and high (i.e., the stand basal area after the thinning was, on average, 40, 27, and 24 m2·ha–1, respectively, in Heinola, and 30, 28, and 17 m2·ha–1 in Punkaharju, respectively). Compared with the low thinning intensity, the normal and high thinning intensities increased the basal-area increment of individual trees by 52% and 68%, respectively. Normal and high thinning intensities resulted in a relatively small reduction (1%–4%) of mean ring density compared with low thinning intensity. The random variation in wood density between and within trees was large. About 27% of the total variation in wood density was related to variation between rings. Our results indicate that the prevailing thinning intensities in Norway spruce stands in Fennoscandia cause no marked changes in wood density. At least, the possible reduction in wood density is low compared with the increase in individual tree growth.

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